From JIM LIPTRAP's "My Genealogy" web page http://jliptrap.us/gen/
There have been many guesses about the meaning of the name "Steinseifer." But records from the area west of Siegen, Nassau, Germany, in the first half of the 1600's point to a family that lived in a particular, small, rocky valley near Brachbach on the Sieg River. The family of "Johannes zum Steinseiffen," a miller in Brachbach, is mentioned in the churchbooks in Kirchen from their beginning in 1642. A more complete description would be a family from the "steinigen Seifen." "Steinig" means stony or rocky. "Seifen" is an old German word, not in current dictionaries, meaning a small valley off to the side.